@SunshineOceanAndOranges I completely agree with you re the timing. First 6-12 months are fab, then you dip a bit as you start to get into a routine and miss home etc. That lasts for a while, often with ups and downs. Then things seem stable but there's still this weird lingering effect and for me, 10 years was also a point at which I really struggled. Although, like OP, I also had a 2 year old at that point and frankly, I really wanted to go home. I even looked into a job which would have been an amazing opportunity but it was in the wrong city. Even DH, who has always been completely clear that he did not want to go back, at that point, was wiling to consider it.
So OP - I think that the 2 year old is probalby a bit part of this combined with the 10 year. I found at 10 years and with a small child the sort of fn partying life with my "new" friends had fallen away but I hadn't found a core group of people who were local and part of my new parenting life. Combined with the relentless weather, the feeling like my home was always too small/too cluttered etc...
And right now, the CoL thing is making everything harder. At least when that was me, we were able to afford trips back home fairly frequently, as well as other holidays. We had money to go out and do things and have lots of activities. I used to go out to meet friends for lunch/drinks/coffee/dinner on a regular basis, with or without DS.
NOw, I feel settled here (20+ years) but my earnings haven't really changed notably and DH and I are really feeling it. We couldn't afford a trip home right now and I honestly worry that if one of our parents fall ill we're screwed as I don't see how we'd even get out there to help. Drinks/dinners/coffees are severely limited, days out too. I mean, our mortgage increased by 50% last year, not to mention all the other insane increases in insurance, council tax, utilities etc. And suddnely I find myself thinking that if we went home, we'd be better off.